JAVA基于 Socket开发C/S模式的聊天程序出现的一个错误，希望大家帮忙找出来！！

代码：
服务端：

 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;
 import java.net.*;
 import java.io.*;
 public class Server
 {
     public static void main(String []args)
     {
         try
        {
             ServerSocket server=new ServerSocket(4002);
             System.out.println("Server is starting");
             Socket client=server.accept();
            System.out.println("Connected the client");
             String msg;
             BufferedReader sin=new BufferedReader(new InputStreamReader(System.in));
             BufferedReader cin=new BufferedReader(new InputStreamReader(client.getInputStream()));
             PrintWriter sout=new PrintWriter(client.getOutputStream());
             System.out.println("Client say: "+cin.readLine());
             msg=sin.readLine();
             while(!msg.equals("bye"))
             {
                 sout.println(msg);
                 sout.flush();
                 System.out.println("You say:"+msg);
                 System.out.println("Client say : "+cin.readLine());
                 msg=sin.readLine();
             }
             System.out.println("The chat is end");
             sin.close();
             cin.close();
             sout.close();
             client.close();
             server.close();
        }
         catch(IOException e)
        {
             System.out.println("Error"+e.toString());
        }
     }
 }

客户端：

 import java.awt.*;
 import java.awt.event.*;
 import javax.swing.*;
 import java.net.*;
 import java.io.*;
public class Client
{
    public static void main(String [] args)
    {
        try
        {
            Socket client=new Socket("127.0.0.1",4002);
            BufferedReader cin=new BufferedReader(new InputStreamReader(System.in));
            BufferedReader sin=new BufferedReader(new InputStreamReader(client.getInputStream()));
            PrintWriter cout=new PrintWriter(client.getOutputStream());
            String msg;
            System.out.println("Connect Server .");
            msg=cin.readLine();
            while(!msg.equals("bye"))
            {
                cout.println(msg);
                cout.close();
                System.out.println("You say: "+msg);
                System.out.println("Server say:"+sin.readLine());
                msg=cin.readLine();
            }
            System.out.println("The chat is end");
            cin.close();
            sin.close();
            cout.println();
            client.close();
        }
        catch(Exception e)
        {
            System.out.println("Error:"+e.getMessage());
        }
        
    }
}

我发完一次数据后，客户端提示：Socket Close.
然后，服务端发数据后，就出现
Errorjava.net.SocketException: Software caused connection abort: recv failed
我是菜鸟。诚恳请教！
困然很久了。。查了资料。但是还是不清楚为什么。这代码是参考教程写的